Even if there are 1 million independent email servers, if Google, Microsoft, Amazon, and Apple send, receive, or pass along 98-99% of emails, there's still a fair bit of centralization in the network which should be acknowledged, though this is admittedly not the same as the protocol being inherently centralized.

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atoav 2 days ago | parent [-]

How do you messure this? Every university in my country has thousands of mail accounts that are constantly used and having worked at an university IT department I have never heard of any numbers collection coming by to ask us how many mails our users sent to each other.

I wouldn't be surprised if that percentage was made up by the big ones to give you the feeling that self hosting mailservers is useless.

	▲	pcthrowaway 2 days ago \| parent [-]
		You're probably right, I hadn't considered the volume of mail being sent within institutions that might host their own mailservers, so maybe we should say more than like 50-60%. Is it still a good example of federation though if a vast majority (99%?) of mails between such institutions or outside of orgs large enough to have a campus, tend to go through Microsoft/Google/Apple/Amazon?